DSpace Collection:http://hdl.handle.net/10204/3826
Mon, 05 Dec 2016 22:05:46 GMT2016-12-05T22:05:46ZBulk feeder or selective grazer: African buffalo space use patterns based on fine-scale remotely sensed data on forage quality and quantityhttp://hdl.handle.net/10204/8746
Title: Bulk feeder or selective grazer: African buffalo space use patterns based on fine-scale remotely sensed data on forage quality and quantity
Authors: Kaszta, Z; Marino, J; Ramoelo, A; Wolff, E
Abstract: The distribution and behaviour of African large grazers are regulated primarily from the bottom up, with some species showing clear preferences for certain vegetation types. While the African buffalo (Syncerus caffer) is sometimes considered a bulk grazer, other studies indicate that they can be selective and show seasonal variations in their home ranges. We used very high resolution satellite imagery to evaluate how the quality and quantity of the vegetation influence space use by buffalo herds in Kruger National Park, testing the bulk-selective hypotheses. Using telemetry data from six buffalo, we analyzed seasonal differences in home ranges and core areas. We investigated resource selection and preference at various spatial scales for a subset of three buffalo, comparing habitat use against vegetation biomass and nitrogen content, derived from a high resolution RapidEye image of the wet season. Overall buffalo preferred open vegetation types, with sparse trees and fertile soils, and had home ranges that partially overlapped between dry and wet seasons (average overlap 50%). Buffalo formed home ranges non-randomly within the study area, choosing vegetation of higher quality and quantity. Within home ranges, however, they selected for higher quality forage, and not for higher quantity. Our results showed that the dichotomy between unselective bulk grazers or selective feeders can be scale dependent, as buffalo behaved more like bulk feeders at the scale of home ranges but were more selective within their home range, preferring quality over quantity.
Description: Copyright: 2016 Elsevier. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website. The definitive version of the work is published in Ecological Modelling, Vol 323, pp. 115–122Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/10204/87462016-03-01T00:00:00ZThe consideration of non-anthropogenic emissions for air quality modelling in South Africahttp://hdl.handle.net/10204/8712
Title: The consideration of non-anthropogenic emissions for air quality modelling in South Africa
Authors: Naidoo, M; Piketh, S
Abstract: Air quality modelling requires the identification of all relevant sources of emissions and the accurate calculation of the emissions rates. Many of these sources include anthropogenic activities that need to be accounted for in any emissions inventory to appraise their impact on air quality. Frequently the anthropogenic sources are the easiest to control through various emissions mitigation strategies. However emissions from natural sources can also contribute significantly to air pollution levels and are thus just as important to quantify to avoid underestimation in air quality in simulations. Biomass burning plays a key role in southern Africa's environmental concerns (highlighted by both the Southern African Regional Science Initiative field campaigns, SAFARI¿92 and SAFARI2000) as it is associated with land-cover change as well as the release of pollutants into the atmosphere within a relatively short period of time. Biomass burning emissions inclusion in any air quality modelling over southern Africa is necessary. Biogenic emissions can be considered as just as important, especially, if chemical transformation modelling is required. Biogenic Volatile Organic Carbon (BVOC) emissions as well as NOx from the soil may contribute significantly (depending on vegetation and soil types) within a model domain. Together, biomass burning and biogenic emissions establish a baseline emissions inventory onto which anthropogenic emissions can be added. This paper provides a description of various models and data sources for deriving model ready emissions inventories for biomass burning and biogenic emissions. The results from these models are also presented and discussed.
Description: 2015 National Association for Clean Air Conference, President Hotel, Bloemfontein, Free State, 1 - 2 October 2015. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's websiteThu, 01 Oct 2015 00:00:00 GMThttp://hdl.handle.net/10204/87122015-10-01T00:00:00ZA brief review of remote sensing data and techniques for wetlands identificationhttp://hdl.handle.net/10204/8567
Title: A brief review of remote sensing data and techniques for wetlands identification
Authors: Ritchie, M; Das, S
Abstract: This paper reviews some data issues and associated techniques which have been implemented in the field of remote sensing for the identification of wetlands. Wetlands are found in diverse geographic areas, however in situ measurements from wetlands may often be hard to obtain. A review of some data sources and associated techniques revealed that satellite data is a good means of identifying wetlands. Further, various data sources may be complimentary in nature, and by combining data from various sources (including ancillary data), better identification of wetlands can be achieved. While multi-temporal imageries aid in the detection wetlands, the date(s) of imagery could have a large effect on the accuracy of the classification of wetlands. Various techniques for wetland identification exist, some of which are statistically based while others may be rule-based or machine learning based. Hybrid techniques combining unsupervised and supervised classification are gaining popularity along with rule-based methods due to their higher accuracies in classification.
Description: 14th Biennial Geophysical Conference (SAGA 2015), 6-9 September 2015Tue, 01 Sep 2015 00:00:00 GMThttp://hdl.handle.net/10204/85672015-09-01T00:00:00ZEffect of impervious surface area and vegetation changes on mean surface temperature over Tshwane metropolis, Gauteng Province, South Africahttp://hdl.handle.net/10204/8521
Title: Effect of impervious surface area and vegetation changes on mean surface temperature over Tshwane metropolis, Gauteng Province, South Africa
Authors: Adeyemi, A; Botai, J; Ramoelo, A; van der Merwe, F; Tsela, P
Abstract: The Tshwane Metropolis, Gauteng Province, South Africa, continues to experience rapid urbanization as a result of population growth. This has led to the conversion of natural lands into large man-made landscapes i.e., increase in impervious surfaces and a decrease in vegetative cover. This land use or land cover changes are also thought to affect the climate of the Tshwane metropolis as is evidenced by heat waves in 2013 and 2014. This paper describes how vegetation and impervious surface area (ISA) or built up areas were classified from Landsat 8 LCDM, 2013, and Landsat 7 ETM+, 2003 images using thematic spectral indices and mean surface temperatures derived from the thermal bands. The linear relationship between the two land cover types and surface temperature (LST) derived from the thermal bands was also examined. The results of this research reveal that the ISA increase has occurred due to urban sprawl and this have contributed to increase in surface temperature.
Description: Copyright: 2015 CONSAS conference. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website. The definitive version of the work is published in South African Journal of Geomatics, 4(4), pp 1-18Sun, 01 Nov 2015 00:00:00 GMThttp://hdl.handle.net/10204/85212015-11-01T00:00:00ZMultitemporal burnt area mapping using Landsat 8: merging multiple burnt area indices to highlight burnt areashttp://hdl.handle.net/10204/8495
Title: Multitemporal burnt area mapping using Landsat 8: merging multiple burnt area indices to highlight burnt areas
Authors: Vhengani, L; Frost, P; Lai, C; Booi, N; Van den Dool, R; Raath, W
Abstract: Wild fires may be beneficial to some ecological functions, however their negative impacts far exceed their benefits. This is because wildfires are a threat to the natural environment, wild life and their carbon emissions contribute to green house gases. These, makes the study of wildfires important. The study of fires is in three phases. Firstly it is forecasting, which uses Fire Danger Index (FDI), secondly it is the mapping of active fires and thirdly, the mapping of burnt areas to access the impact. The focus of this paper is burnt area mapping. The objective is to demonstrate how multiple burnt area indices were merged to highlight burnt areas.
Description: 2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Milan, Italy, 26-31 July 2015. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's websiteWed, 01 Jul 2015 00:00:00 GMThttp://hdl.handle.net/10204/84952015-07-01T00:00:00ZSpectral mapping of savanna tree species at canopy level, with focus on tall trees, using an integrated CAO Hyperspectral & LiDAR sensor approachhttp://hdl.handle.net/10204/8494
Title: Spectral mapping of savanna tree species at canopy level, with focus on tall trees, using an integrated CAO Hyperspectral & LiDAR sensor approach
Authors: Naidoo, L; Mathieu, R; Cho, M; Asner, G; Eckardt, F
Abstract: The detection and mapping of tree/plant species in the savanna ecosystem can provide numerous benefits for the managerial authorities. This includes the accurate mapping of the spatial distribution of economically viable trees which are a key source of food production and fuel wood for the local populace and communities. Economically viable tree species can thus be sustainably monitored while the pest species can be targeted and removed. The aim of this study was to identify spectrally and map 5 tall savanna tree species in the Greater Kruger National Park region using a decision tree approach. It was found that remote sensing is the best possible tool for discriminating and mapping the individual canopies of the different tree species of interest. The method proposed is in its prototype phase but its refinement and implementation over a larger sample of tree species is planned for the near future.
Description: 8th Annual Savanna Science Networking Meeting, Skukuza, Kruger National Park, Mpumalanga, South Africa, 8-12 March 2010Mon, 01 Mar 2010 00:00:00 GMThttp://hdl.handle.net/10204/84942010-03-01T00:00:00Z